Recently I converted from a PS/2 to a USB keyboard - that's been the only change.

As far as I can tell, there should be no difference to Windows if the PC has been sleeping for 1 hour or 12 hours, there are no different settings that kick in after a longer period of time. These are the default settings for Balanced. I only have it set to sleep after 30 minutes (hybrid sleep actually). For short sleeps (a couple of hours), everything works as it should. Only after that can I hit the power button and it resumes. I actually have to switch off the power supply and then turn it back on. Nothing seems to wake it - the mouse, the keyboard, or the power button - I get no fans or anything, the system seems locked up tight. Recently, I've been having trouble waking the computer from longer sleeps (overnight). A few taps on the keyboard or a push of the flashing power button would wake it up.

I'd walk away from the computer for a while, or leave it on overnight, and come back to find it asleep. The sleep functionality (using the default Balanced mode) had been working fine as far as I could tell. Running Windows 7, set up mostly as default. I recently built my first PC - AMD FX8350 on an Asus M5A88M motherboard.

How to increase sleep time in windows 7